question for Luxman L-590AX owners


I own the subject amp, have had it for 3-4 years. I recently noticed a low hum or buzz coming from the amp itself (not the speakers), and would swear that it has been dead quiet up until now. You have to have your head right down beside it to hear it. I'd like to hear what other owners have to say. Are your amps completely quiet? Seems like I may have developed an issue. Thanks in advance, and Merry Christmas.
builder3
I might have to live with it, I guess. I was considering buying the new AXMarkII, sounds like that would just be a very expensive crapshoot. I don't think it has a thing to do with any outside factor. I think it's the transformer. I can't hear mine unless I stick my head right beside it.
I emailed LuxmanUSA probably 3 weeks ago. Actually went through their page to request information on a repair. Crickets. Hey, if your customers are a bother, just ignore them, they'll go away.
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Even though I used the same word, it's not really a buzz. It's a hum that I have to be within a foot to hear, and have nothing playing. Still bothers me though, the idea that it's not dead quiet.
I guess I must be lucky then. Zero hum or buzz on my AXII even if I put my ear right next to it. 
I was the same, until a couple months ago. I'd like to have the newer AXII, even though I choke at the money, but a couple guys here say theirs have the same hum. I bought this amp used, it's immaculate, think it was $4300. Not sure what I'm going to do, it's eating at me, lol. Might be nice to hear something from Luxman, too, obviously.
Thanks to everyone for the input.